Materials and structures of bands which are conventionally used in wrist watch-type electronic apparatus and which contain conductive members therein, structures for mounting a band on the case of a wrist watch type electronic apparatus, and structures of band mounting portions of the case of a wrist watch type electronic apparatus are proposed in Japanese Laid-Open Utility Model Nos. 56-114492, 56-114493, 58-65908, 58-77492 and 62-71589, Japanese Laid-Open Patent Nos. 63-197103 and 1-279603, and Japanese Laid-Open Utility Model Nos. 3-30890, 3-30891 and 3-30892.
All materials of the bands disclosed in the above publications are non-metallic materials such as natural leather, artificial leather, insulating high-molecular resins, and elastomer fibers.
The band structures disclosed include a structure in which a magnetic powder is contained in leather, and a metallic piece is added to the widthwise side of a band, a structure in which a flexible metallic plate such as a foil or mesh is contained in leather, a structure in which a conductive high-molecular resin is contained in an insulating high-molecular resin, a structure in which a flexible circuit substrate is contained in a resin, a structure in which a flexible sheet is contained in a synthetic resin to provide a switching function, and a structure in which a wire is contained in a fabric having elasticity and comprising elastomer fibers.
Japanese Patent Laid-Open Nos. 63-197103 and 1-279603 also disclose a structure in which a conductor is passed zigzag through continuous links of a metallic expansion band.
The structures for mounting a band on the case of a wrist watch type electronic apparatus include: a structure in which a band is mounted by a spring bar; a structure in which a band is mounted by holding it between a case band and a case back, both of which form a case of a wrist watch type electronic apparatus; a structure in which a band is screwed to a case of a wrist watch type electronic apparatus; and a structure in which a case of a wrist watch-type electronic apparatus and a band are integrated by holding the case of the wrist watch type electronic apparatus from the upper and lower sides thereof.
All band mounting portions of the cases of wrist watch-type electronic apparatus have a known "Roof-attached Horn style" structure on the case of a wrist watch, except a structure in which the band and the case of the wrist watch-type electronic apparatus are integrated by holding a case of the wrist watch-type electronic apparatus from the upper and lower sides thereof.
Some electronic wrist watches have a solar cell, or a generating device provided in the case of the watch so as to convert rotation of an oscillating weight into a coil current. In a watch having a generating device, the electric power generated by the generating device is stored in a secondary battery (for example, a large-capacity capacitor having an electrical double layer) which is contained in the case of the watch so that the driving motor, IC and a display of the watch are driven by the stored electric power.
On the other hand, in regard to usual electronic wrist watches, Japanese Utility Model Laid-Open Nos. 58-77493 and 3-30892 disclose a structure in which a circuit is contained in a band, and Japanese Utility Model Laid-Open Nos. 59-137588 and 59-137589 disclose a structure in which a piezoelectric element, an electromagnet coil, a rectifying circuit and a battery are contained in a band.
The material and structure of a band containing a conductive member, which are used for conventional wrist watch-type electronic apparatus, the structure for mounting the band on the case of the wrist watch-type electronic apparatus, and the structure of the band mounting portion of the case of the wrist watch-type electronic apparatus have the following problems to be solved with respect to the properties of fitting on an arm, the suitability of the band, strength, durability, limits on design and so on.
First, the band material has the problem that although most conventional bands are made of a non-metallic material from the viewpoint of the need to ensure insulating properties, the band design which is important for creating demand can be selected from only a narrow range in view of the present situation where metallic bands are frequently used for wrist watches for reasons of use environment, durability and design. This is undesirable for merchandise variation.
Second, each of the above structures of the bands has the following problem:
1) The structure in which a metallic plate is attached to the widthwise side of a leather or synthetic resin band has the problem that fitness deteriorates due to an increase in flexural rigidity.
2) Where a metallic plate is contained in a leather or synthetic resin base, although the use of a thin metallic plate causes the same degree of suitability as that of a band comprising only leather or synthetic resin, the metallic plate is cut or cracked by bending or twisting of a band or continuous use for a long period of time, thereby causing the problem of durability.
3) The band structure in which elastic fibers comprising an elastomer resin are used has faults peculiar to such an expansion band. In other words, when it is desired to adjust the length and elasticity of the band in accordance with the thickness of an arm and liking, a plurality of bands having different lengths and degrees of elasticity must be previously prepared. In addition, since the band must invariably be expanded at the time of setting on an arm or separating therefrom, it is necessary to increase the flexibility of the internal structure contained in the band and to ensure durability to deformation.
4) Although a wire is provided zigzag in the expansion band in order to ensure flexibility and durability to deformation, tensile stress more or less acts on the wire at the time of setting on an arm or removing therefrom, while contraction and expansion properties cannot be supplied to the wire itself. If large deformation is repeatedly produced by continuous use of the band, therefore, the zigzag form cannot be maintained, and unevenness occurs in the zigzag form, thereby affecting the fit. In addition, since the wire in the terminal fixing portion of a fabric is fixed, if large stress is applied to the wrist watch-type electronic apparatus by dropping it onto a floor, the wire itself in the terminal fixing portion might be deformed.
In the structure in which a wire is woven in a zigzag manner into a fabric, the displacement amount and displacement process of the fabric, which change in accordance with the tensile force acting at the time of setting or removing the band, are different from those of the wire. When the band length at the time of no load is different from the length at the time of setting (i.e. the band is stretched when set on an arm), distortion occurs in the band, and fit thus deteriorates. For the same reason, there is also the fault that the fabric in which the wire is woven is cut in a portion near the wire.
Where a wire woven in a helical form is passed through a sleeve-like fabric, there is the problem that fit deteriorates due to an increase in flexural rigidity.
5) The structure disclosed in Japanese Laid-Open Patent Nos. 63-197103 and 1-279603 in which a conductor is disposed zigzag in continuous links of a metallic expansion band has not only the same problems as those described above with respect to the expansion band, but also the problem that since the link mechanism of the metallic expansion band is complicated, and the wire must be contained zigzag in the link mechanism, the assembly step is complicated, and the cost is thus increased. Further, the metallic expansion band has a simple plane form and thus has no feeling of high grade, and it is difficult to attempt to diversify the design of the band.
Third, each of the above conventional band mounting structures of the bodies of the wrist watch type-electronic apparatus has the following problems:
1) Where a spring bar is used, since the band rotates around a spring bar relative to the watch case, the required electrical connection between the watch case and the band cannot achieve the predetermined purpose unless the watch case and the band always contact under a predetermined pressure. Since the band is rotatably mounted on the watch case under a predetermined contact pressure, the rotation of the band inevitably becomes awkward. In continuous use for a long period of time, since relative rotation between contact terminals under the contact pressure is repeated, the contact terminals are worn, and the contact pressure decreases with use. In addition, the need for relative rotation between the contact terminals makes it difficult to provide reliable waterproofness.
2) Where the band is mounted by holding it between a case band and a case back, both of which form the watch case, the band must be mounted on the watch case at a predetermined angle with respect to an arm. However, a leather or synthetic resin band cannot sufficiently bend by its own weight because of the presence of a conductive member therein, and a snap closure must be operated while forcing the band to bend along the arm. Thus, the mounting work is difficult, and the watch may be dropped due to the difficulties in the work. In this case, there are problems that the conductive member in the band is cut or cracked due to twisting, expansion and contraction which are produced by bending of the band mounting portion of the watch case. For example, when a silicon resin band is used, the band body itself might be cracked.
3) Where a band is screwed to the watch case, and where the watch case and the band are integrated by holding the watch case from the upper and lower sides thereof, there are faults which are basically the same as those described in paragraph 2 above.
Fourth, the structure of the band mounting portion of the wrist watch type electronic apparatus has the following problems: Although the cases of conventional watches are made of a metal with high rigidity, the bands disclosed in most documents are made of non-metal materials having strength lower than that of the cases. When either the front or the rear of a non-metallic band is fixed to the watch case, the maximum bending moment acts on a portion near the band fixing portion due to bending of the band, and thus the band is easily broken at that position. This causes the need for a "Roof-attached Horn style" structure as the band mounting structure of the watch case in which the band is held between a roof portion and a case back. As a result, the very important plane design of the watch case which visually appeals to consumers is significantly limited, thereby resulting in the fault that the design cannot be varied.
An electronic wrist watch containing a battery has the following problems: Although the electronic wrist watch containing a generating device preferably has a secondary battery having as large a capacity as possible, the capacity is limited because the battery is contained in the watch case. In addition, since only a specified secondary battery can be used for satisfying performance, such as the allowable number of recharges and so on, the storage capacity is not sufficient. For example, an ordinary wrist watch can be driven for only a few days in a state where it is removed from an arm. A limiter circuit is contained for preventing the secondary battery from being overcharged by the electric power generated from the generating device so that excess electric power is discarded. For example, during the period that a person with the watch set on the arm normally uses the watch, about half of the electric power generated from the generating device is discarded.
Although it is recognized that the wrist watch disclosed in each of the above documents is advanced in that a space for containing a battery and so on is formed in the band apart from the watch case, no measure is taken for durability and against accidents such as cutting of a circuit or wiring in the band, the troubles in the generating portion caused by bending of the band, etc., which are actually caused in the band containing a battery.
The present invention has been achieved in consideration of the above problems, and an object of the present invention is to solve the problems of the band itself or the mounting structure in a wrist watch type-electronic apparatus having a band containing conductive members therein, and to realize an internal structure of a band which has high durability and which reduces breaking of wire and trouble.